Conventional techniques for generating an image of an object generally rely solely on mechanical and chemical processes. For example, a conventional camera may include a lens that focuses light generated and/or reflected by an object on film, and the film, through a chemical reaction on the surface of the film, records the pattern of light striking the film. The film then can be processed to generate an image of the object. In recent years, electronic imaging sensors, such as charge couple devices (CCDs), have provided an alternative technique for generating an image of an object. For example, a digital camera may include a lens that focuses light generated and/or reflected by an object on an electronic image sensor (rather than film), and the electronic image sensor records the pattern of light striking the sensor by generating a pattern of charges corresponding to the pattern of light striking the sensor.
Imaging techniques using electronic imaging sensors may be advantageous over certain conventional techniques for a number of reasons, including the elimination of the need to process and replace film. In certain applications, these advantages may be particularly important. For example, electronic imaging sensors may allow Earth-orbiting satellites to have on-board cameras for generating images of earth, an application that may be difficult or impossible using conventional imaging techniques (as there would be great difficulty in processing and replacing film for a camera on-board an Earth-orbiting satellite).